US6938510B2 - Ball screw apparatus - Google Patents

Ball screw apparatus Download PDF

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Publication number
US6938510B2
US6938510B2 US10/437,032 US43703203A US6938510B2 US 6938510 B2 US6938510 B2 US 6938510B2 US 43703203 A US43703203 A US 43703203A US 6938510 B2 US6938510 B2 US 6938510B2
Authority
US
United States
Prior art keywords
nut
snap ring
circulation piece
circulation
ball
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime, expires
Application number
US10/437,032
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English (en)
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US20030213322A1 (en
Inventor
Takayuki Yabe
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NSK Ltd
Original Assignee
NSK Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NSK Ltd filed Critical NSK Ltd
Assigned to NSK LTD. reassignment NSK LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: YABE, TAKAYUKI
Publication of US20030213322A1 publication Critical patent/US20030213322A1/en
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Publication of US6938510B2 publication Critical patent/US6938510B2/en
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Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H25/00—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms
    • F16H25/18—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for conveying or interconverting oscillating or reciprocating motions
    • F16H25/20—Screw mechanisms
    • F16H25/22—Screw mechanisms with balls, rollers, or similar members between the co-operating parts; Elements essential to the use of such members
    • F16H25/2204—Screw mechanisms with balls, rollers, or similar members between the co-operating parts; Elements essential to the use of such members with balls
    • F16H25/2214—Screw mechanisms with balls, rollers, or similar members between the co-operating parts; Elements essential to the use of such members with balls with elements for guiding the circulating balls
    • F16H25/2219—Axially mounted end-deflectors
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T74/00—Machine element or mechanism
    • Y10T74/19—Gearing
    • Y10T74/19642—Directly cooperating gears
    • Y10T74/19698—Spiral
    • Y10T74/19702—Screw and nut
    • Y10T74/19744—Rolling element engaging thread
    • Y10T74/19749—Recirculating rolling elements
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T74/00—Machine element or mechanism
    • Y10T74/19—Gearing
    • Y10T74/19642—Directly cooperating gears
    • Y10T74/19698—Spiral
    • Y10T74/19702—Screw and nut
    • Y10T74/19744—Rolling element engaging thread
    • Y10T74/19749—Recirculating rolling elements
    • Y10T74/19767—Return path geometry

Definitions

  • the present invention relates to a ball screw apparatus which is used in industrial machines and the like.
  • a screw shaft includes a screw groove formed in the outer peripheral surface thereof and extends in the axial direction of the ball screw apparatus
  • a nut includes a screw groove formed in the inner peripheral surface thereof so as to correspond to the screw groove of the screw shaft
  • the nut is fitted with the screw shaft
  • the screw groove of the nut and the screw groove of the screw shaft are opposed to each other to thereby form a spiral-shaped load raceway between them.
  • the load raceway there are disposed a large number of balls in such a manner that they are able to roll and, due to rotation of the screw shaft (or nut), the nut (or screw shaft) can be moved in the axial direction of the ball screw apparatus through the rolling movements of the balls.
  • a method for circulating the balls endlessly there are generally known a method of a circulation tube type and a method of an end cap type.
  • a ball return passage which penetrates through the nut in the axial direction thereof and, at the same time, a cut-away portion is formed in the end face of the nut, and a resin-made circulation piece including a ball circulation passage allowing the ball return passage and the load raceway formed between the two grooves is fitted with and fixed to the cut-away portion, whereby the load raceway, ball return passage and ball circulation passage cooperate together in forming an endless circulation passage for the balls.
  • the present invention aims at eliminating the drawbacks found in the above-mentioned ball screw apparatus. Accordingly, it is an object of the present invention to provide a ball screw apparatus which can restrict the axial-direction position shift of the circulation piece due to heat to thereby be able to enhance the reliability of the ball screw apparatus.
  • a ball screw apparatus having: a screw shaft including a spiral-shaped screw groove formed in an outer peripheral surface thereof; a nut fitted with the screw shaft, the nut including a screw groove formed in an inner peripheral surface thereof so as to correspond to the screw groove of the screw shaft and a ball return passage formed so as to penetrate through the nut in an axial direction thereof; a circulation piece fitted with an end face of the nut, the circulation piece including a ball circulation passage allowing the two screw grooves and the ball return passage to communicate with each other; and, a large number of balls circulatably loaded while rolling between the two screw grooves, along the ball return passage and the ball circulation passage, wherein, in the inner peripheral surface of the nut, a concave-shaped snap ring groove extending along the peripheral direction of the nut is formed, in the face of the circulation piece that faces the inside diameter side of the nut, a concave-shaped snap ring groove is formed so as to connect
  • the snap ring is made of resin or metal
  • retaining pieces or a connected body of the retaining pieces are interposed between the mutually adjoining ones of the large number of balls.
  • the concave-shaped snap ring groove of the circulation piece may be formed at a position near to the axial-direction central portion of the circulation piece.
  • FIG. 1 is an explanatory view of an embodiment of a ball screw apparatus according to the present invention, when it is viewed from the axial direction thereof;
  • FIG. 2 is a right side view of the ball screw apparatus, in part taken along the arrow line X—X shown in FIG. 1 ;
  • FIGS. 3 ( a )- 3 ( d ) show circulation pieces, specifically, FIG. 3B is a front view thereof, FIG. 3A a left side view of FIG. 3B , FIG. 3C is a right side view of FIG. 3B , and FIG. 3D is a bottom View of FIG. 3 B:
  • FIG. 4 shows a snap ring
  • FIGS. 5 ( a )- 5 ( b ) are explanatory views of the operation effect of the present invention, specifically, FIG. 5A is a section view of a portion of a ball screw apparatus according to the present invention, and FIG. 5B is a section view of a portion of a conventional ball screw apparatus;
  • FIG. 6 is an explanatory view of a second embodiment of a ball screw apparatus according to the present invention, when it is viewed from the axial direction thereof;
  • FIG. 7 is a section view taken along the arrow line X—X shown in FIG. 6 ;
  • FIG. 8 shows an example of a retaining piece.
  • FIG. 1 is an explanatory view of an embodiment of a ball screw apparatus according to the present invention, when it is viewed from the axial direction thereof;
  • FIG. 2 is a right side view of the ball screw apparatus, in part taken along the arrow line X—X shown in FIG. 1 ;
  • FIG. 3 shows a circulation piece, specifically, FIG. 3B is a front view thereof, FIG. 3A a left side view of FIG. 3B , FIG. 3C is a right side view of FIG. 3B , and FIG. 3D is a bottom view of FIG. 3B ;
  • FIG. 4 shows a snap ring;
  • FIG. 3B is a front view thereof
  • FIG. 3A a left side view of FIG. 3B
  • FIG. 3C is a right side view of FIG. 3B
  • FIG. 3D is a bottom view of FIG. 3B
  • FIG. 4 shows a snap ring
  • FIG. 5 is an explanatory view of the operation effect of the present invention, specifically, FIG. 5A is a section view of a portion of a ball screw apparatus according to the present invention, and FIG. 5B is a section view of a portion of a conventional ball screw apparatus;
  • FIG. 6 is an explanatory view of a second embodiment of a ball screw apparatus according to the present invention, when it is viewed from the axial direction thereof;
  • FIG. 7 is a section view taken along the arrow line X—X shown in FIG. 6 ; and, FIG. 8 shows an example of a retaining piece.
  • the present ball screw apparatus 10 comprises a screw shaft 13 including a spiral-shaped screw groove 12 formed in the outer peripheral surface thereof and extending in the axial direction of the ball screw apparatus 10 and a nut 16 including a screw groove 14 formed in the inner peripheral surface thereof as to correspond to the screw groove 12 formed in the screw shaft 13 , while the nut 16 is fitted into the screw shaft 13 .
  • the screw groove 14 of the nut 16 and the screw groove 12 of the screw shaft 13 are disposed opposed to each other to thereby form a spiral-shaped load raceway between them and, in the load raceway, there are disposed a large number of balls 15 serving as rolling bodies. And, as the screw shaft 13 (or nut 16 ) is rotated, the nut 16 (or screw shaft 13 ) is moved in the axial direction through the rolling motion of the balls 15 .
  • the circulation piece 18 is composed of a molding which is made of, for example, synthetic resin; and, the circulation piece 18 , as shown in FIG. 3 , comprises a tongue portion 20 for scooping up the balls 15 rolling on the load raceway formed between the two screw grooves 12 , 14 , and a curved-shaped ball circulation groove (ball circulation passage) 21 allowing the ball return passage 17 to communicate with the load raceway formed between the two screw grooves 12 , 14 .
  • the tongue portion 20 , ball circulation groove 21 , load raceway formed between the two screw grooves 12 , 14 , and ball return passage 17 cooperate together in forming an endless circulation passage for the balls 15 .
  • the circulation piece 18 is restricted not only in the diameter direction but also in the peripheral direction within the cut-away portion 19 .
  • a concave-shaped snap ring groove 23 along the circumferential direction of the nut 16 and, at the same time, in the surface of the circulation piece 18 that faces the inside diameter side of the nut 16 , there is formed a concave-shaped snap ring groove 23 which extends along the snap ring groove 22 on the nut 16 side.
  • the thickness of the side of the circulation portion 18 that faces the end face side of the nut 16 is set slightly larger than that of the remaining portions thereof. Therefore, the contact area (friction surface) of the circulation piece 18 with respect to the inner peripheral surface of the nut 16 is slightly wider than a conventional circulation piece.
  • the snap ring groove 22 on the nut 16 side continues with the peripheral-direction two sides of the snap ring groove 23 on the circulation piece 18 side, whereby the two snap ring grooves 22 , 23 cooperate together in forming a C-like shape which corresponds to a snap ring 30 .
  • the snap ring 30 there can be used a snap ring having one of various section shapes such as a circular section shape or an angular-shaped section shape.
  • the snap ring 30 elastically presses the circulation piece 18 outwardly in the diameter direction thereof to thereby press the circulation piece 18 against the inner peripheral surface of the nut 16 .
  • the material of the snap ring 30 depending on the productivity and temperature environment, there can be used synthetic resin (for example, polyacetal) or metal (for example, spring steel).
  • synthetic resin for example, polyacetal
  • metal for example, spring steel
  • the snap ring 30 can be mass produced at a low cost, while it does not impair other parts nor raises a fear of seizure.
  • the snap ring 30 can also be used as a seal member.
  • the snap ring 30 in the case of a snap ring 30 made of metal, since there is a fear that the snap ring 30 can damage the other parts, there is required a clearance between the inner peripheral portion of the snap ring 30 and screw shaft 13 .
  • the snap ring 30 is excellent in strength, has a strong force going outwardly in the diameter direction of the circulation piece 18 , and is high in thermal strength, the snap ring 30 can be used not only at a temperature of 100° C. or higher but also at a temperature of ⁇ 40° C. or lower. Further, since the snap ring 30 is strong against shock, it is suitable for high speed rotation.
  • FIG. 5A shows a ball screw apparatus according to the present invention in which, for convenience of explanation, the snap ring groove 23 is formed substantially in the axial-direction central portion of the circulation piece 18 and, as described before, by fitting the outside diameter portion of the snap ring 30 into the two snap ring grooves 22 , 23 , the circulation piece 18 is fixed to the nut 16 so as to be restricted in the axial direction thereof.
  • FIG. 5B shows a conventional ball screw apparatus in which a snap ring 40 fitted into the inner peripheral portion of the end portion of the nut 16 is set on a stepped portion 42 formed on the nut 16 end face side of a circulation piece 41 to thereby fix the circulation piece 41 to the nut 16 .
  • the circulation piece 41 is restricted from the end face side of the nut 16 by the snap ring 40 .
  • the circulation piece 18 is restricted at a position near to the axial-direction central portion of the circulation piece 18 by the snap ring 30 .
  • the axial-direction position shift of the circulation piece 18 due to heat can be restricted more than the conventional structure, not only the position shift of the scoop-up portion (tongue portion leading end portion) for scooping up the balls 15 from the load raceway formed between the two screw grooves 12 , 14 of the circulation piece 18 but also a clearance to be generated in the boundary portion between the ball circulation groove 21 of the circulation piece 18 and the ball return passage 17 of the nut 16 can be minimized. As a result of this, the smooth rolling movements of the balls 15 can be secured, which makes it possible to enhance the reliability of the ball screw apparatus.
  • the circulation piece 18 is positively pressed toward the nut 16 side in the diameter direction with a larger force than in the conventional structure and also because, as described above, the contact area of the circulation piece 18 with respect to the inner peripheral surface of the nut 16 is slightly wider than the conventional structure, the pressing force of the circulation piece 18 acts on the nut 16 side in a wider area to thereby increase the frictional force. Further, because the snap ring 30 is fitted into the concave-shaped snap ring groove 23 of the circulation piece 18 , there is no fear that the snap ring 30 can be removed out of position.
  • the structures of the screw shaft, nut, circulation piece, snap ring groove, snap ring and the like of the ball screw apparatus according to the present invention are not limited to the above embodiment but they can be changed properly without departing from the subject matter of the present invention.
  • the concave-shaped snap ring groove 23 is formed on the end face side of the nut 16 near to the axial-direction central portion of the circulation piece 18 and the snap ring 30 is fitted into the snap ring groove 23 and the snap ring groove 22 of the nut 16 .
  • a concave-shaped snap ring groove 23 a may be formed in the axial-direction central portion of a circulation piece 18 a and a snap ring 30 a may be fitted into the snap ring groove 23 a and a snap ring groove 22 a formed on the nut 16 a side.
  • reference character 19 a designates a cut-away portion which is formed in the end face of the nut 16 a and also to which the circulation piece 18 a can be fitted and fixed, and 20 a stands for the tongue portion of the circulation piece 18 a.
  • a retaining piece 100 including arc-shaped or conical-shaped concave surfaces on the two side surfaces thereof opposed to the balls 15 in order to be able to eliminate collision sounds between the balls when driven to thereby reduce the noise of the ball screw apparatus.
  • the retaining piece may be composed of individual retaining pieces which are separately interposed between the balls, or may be composed of a connected body of retaining pieces. In these cases, the position shift and clearance between the circulation piece 18 and nut 16 can be reduced, thereby being able to prevent the retaining pieces 100 and the connected body thereof from being caught.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Transmission Devices (AREA)
US10/437,032 2002-05-15 2003-05-14 Ball screw apparatus Expired - Lifetime US6938510B2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2002139892A JP2003329098A (ja) 2002-05-15 2002-05-15 ボールねじ装置
JPP.2002-139892 2002-05-15

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US20030213322A1 US20030213322A1 (en) 2003-11-20
US6938510B2 true US6938510B2 (en) 2005-09-06

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US10/437,032 Expired - Lifetime US6938510B2 (en) 2002-05-15 2003-05-14 Ball screw apparatus

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US (1) US6938510B2 (de)
EP (1) EP1363046B1 (de)
JP (1) JP2003329098A (de)
DE (1) DE60301517T2 (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050183530A1 (en) * 2004-02-25 2005-08-25 Nsk Ltd. Ball screw and a method for assembling the same
US20080016973A1 (en) * 2006-07-18 2008-01-24 Eichenberger Gewinde Ag Recirculating ball screw and nut drive
US20090158873A1 (en) * 2007-12-20 2009-06-25 Wen-Chia Wu Roller Screw with a Circulating Structure
US20100122596A1 (en) * 2008-11-14 2010-05-20 Ming-Yao Lin Ball Screw
US20130068052A1 (en) * 2011-09-21 2013-03-21 Aktiebolaget Skf Ball screw device with a ring to retain a deviation element for the balls

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3915790B2 (ja) * 2004-02-17 2007-05-16 日本精工株式会社 ボールねじ装置
CN100357632C (zh) * 2004-05-21 2007-12-26 上银科技股份有限公司 共用式组合端塞
JP4822999B2 (ja) * 2006-09-21 2011-11-24 ケーエスエス株式会社 ボールねじ装置
JP5252279B2 (ja) * 2008-08-21 2013-07-31 Ｓｍｃ株式会社 ボールねじ機構
DE102010045318A1 (de) * 2010-09-14 2012-03-15 Robert Bosch Gmbh Gewindetrieb mit Störgeometrie im nichttragenden Bereich der Mutternut
JP2013231456A (ja) * 2012-04-27 2013-11-14 Kuroda Precision Ind Ltd ボールねじ
JP6151161B2 (ja) 2013-11-29 2017-06-21 株式会社ショーワ ボールねじおよびパワーステアリング装置
US20190028008A1 (en) * 2017-07-18 2019-01-24 Hyundai Mobis Co., Ltd In-wheel working device
JP2022061214A (ja) * 2020-10-06 2022-04-18 株式会社ジェイテクト ボールねじ装置
US12546377B2 (en) * 2023-04-13 2026-02-10 Hitachi Astemo, Ltd. Shock absorber

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2924113A (en) * 1960-02-09 Orner
US3170336A (en) * 1962-11-19 1965-02-23 Gen Motors Corp Ball nut and screw assembly
US4677869A (en) 1985-11-25 1987-07-07 Cincinnati Milacron Inc. Linear actuator
US4795172A (en) * 1987-12-07 1989-01-03 Cincinnati Milacron Inc. Grease seal for a power screw system
US5988007A (en) * 1996-06-21 1999-11-23 Thk Co., Ltd. Ball screw apparatus
EP0985851A1 (de) 1998-03-25 2000-03-15 Thk Co., Ltd. Kugelgewindespindel
DE19952714A1 (de) 1999-07-06 2001-02-01 Hiwin Tech Corp Kugelgewindetrieb mit einem Kugelumlenkungsstück

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2924113A (en) * 1960-02-09 Orner
US3170336A (en) * 1962-11-19 1965-02-23 Gen Motors Corp Ball nut and screw assembly
US4677869A (en) 1985-11-25 1987-07-07 Cincinnati Milacron Inc. Linear actuator
US4795172A (en) * 1987-12-07 1989-01-03 Cincinnati Milacron Inc. Grease seal for a power screw system
US5988007A (en) * 1996-06-21 1999-11-23 Thk Co., Ltd. Ball screw apparatus
EP0985851A1 (de) 1998-03-25 2000-03-15 Thk Co., Ltd. Kugelgewindespindel
DE19952714A1 (de) 1999-07-06 2001-02-01 Hiwin Tech Corp Kugelgewindetrieb mit einem Kugelumlenkungsstück

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050183530A1 (en) * 2004-02-25 2005-08-25 Nsk Ltd. Ball screw and a method for assembling the same
US7591205B2 (en) * 2004-02-25 2009-09-22 Nsk Ltd. Ball screw and a method for assembling the same
US20080016973A1 (en) * 2006-07-18 2008-01-24 Eichenberger Gewinde Ag Recirculating ball screw and nut drive
US7614318B2 (en) 2006-07-18 2009-11-10 Eichenberger Gewinde Ag Recirculating ball screw and nut drive
US20090158873A1 (en) * 2007-12-20 2009-06-25 Wen-Chia Wu Roller Screw with a Circulating Structure
US20100122596A1 (en) * 2008-11-14 2010-05-20 Ming-Yao Lin Ball Screw
TWI385324B (zh) * 2008-11-14 2013-02-11 Hiwin Tech Corp 具有鏈條式滾動組之滾珠螺桿迴流結構
US20130068052A1 (en) * 2011-09-21 2013-03-21 Aktiebolaget Skf Ball screw device with a ring to retain a deviation element for the balls

Also Published As

Publication number Publication date
US20030213322A1 (en) 2003-11-20
DE60301517T2 (de) 2006-01-19
EP1363046A3 (de) 2004-03-31
JP2003329098A (ja) 2003-11-19
EP1363046A2 (de) 2003-11-19
DE60301517D1 (de) 2005-10-13
EP1363046B1 (de) 2005-09-07

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